全文获取类型
收费全文 | 5035篇 |
免费 | 374篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 166篇 |
妇产科学 | 86篇 |
基础医学 | 625篇 |
口腔科学 | 155篇 |
临床医学 | 466篇 |
内科学 | 1105篇 |
皮肤病学 | 93篇 |
神经病学 | 277篇 |
特种医学 | 167篇 |
外科学 | 788篇 |
综合类 | 283篇 |
一般理论 | 5篇 |
预防医学 | 417篇 |
眼科学 | 170篇 |
药学 | 302篇 |
中国医学 | 11篇 |
肿瘤学 | 300篇 |
出版年
2023年 | 44篇 |
2022年 | 96篇 |
2021年 | 176篇 |
2020年 | 116篇 |
2019年 | 136篇 |
2018年 | 138篇 |
2017年 | 116篇 |
2016年 | 126篇 |
2015年 | 119篇 |
2014年 | 157篇 |
2013年 | 196篇 |
2012年 | 317篇 |
2011年 | 287篇 |
2010年 | 178篇 |
2009年 | 165篇 |
2008年 | 216篇 |
2007年 | 239篇 |
2006年 | 237篇 |
2005年 | 220篇 |
2004年 | 188篇 |
2003年 | 189篇 |
2002年 | 168篇 |
2001年 | 141篇 |
2000年 | 157篇 |
1999年 | 130篇 |
1998年 | 84篇 |
1997年 | 55篇 |
1996年 | 45篇 |
1995年 | 62篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 60篇 |
1991年 | 65篇 |
1990年 | 73篇 |
1989年 | 75篇 |
1988年 | 50篇 |
1987年 | 62篇 |
1986年 | 52篇 |
1985年 | 46篇 |
1984年 | 34篇 |
1983年 | 27篇 |
1982年 | 36篇 |
1981年 | 31篇 |
1980年 | 32篇 |
1979年 | 33篇 |
1978年 | 23篇 |
1977年 | 25篇 |
1976年 | 23篇 |
1975年 | 21篇 |
1973年 | 20篇 |
排序方式: 共有5441条查询结果,搜索用时 15 毫秒
21.
Baclofen reduced the frequency and aborted the bursts of spontaneous paroxysmal discharges in rat neocortical slices maintained in magnesium-free medium. This action was prevented by pretreatment with barium or caesium, which each increased the ictaform burst frequency, amplitude and duration. 4-Amino-pyridine also increased the burst frequency but reduced the amplitude and did not completely prevent the action of baclofen. Evidently baclofen suppresses such discharges by opening potassium channels normally involved in limiting the burst activity. 相似文献
22.
E K Ong C Suphioglu M B Singh R B Knox 《International archives of allergy and applied immunology》1990,93(4):338-343
A comparison is made of eight different methods to detect allergenic proteins in Western blots of rye-grass pollen extracts. Horseradish peroxidase-based enhanced chemiluminescence (ECL) provides a sensitive method for the detection of allergenic proteins. The method has been modified to use more dilute solutions of ECL substrate to reduce the background, can be applied to a standard nitrocellulose membrane, and used with Kodak X-ray film. The assays can be performed rapidly, replacing use of radiolabelled probes. Increased resolution is obtained. This makes the method suitable for detection of cDNA clones on plaque lifts, and for rapid and specific purification of proteins following immunodetection on nitrocellulose membranes. 相似文献
23.
This study explored the determinants of consumer satisfaction with OTC drugs using the confirmation/disconfirmation model. A revised confirmation/disconfirmation model specifically for OTC drugs was proposed and tested using structural equation modeling with a specific product category: cold medications. The results of this study found that the confirmation/disconfirmation of a consumer's expectation and perceived performance of an OTC drug is important in predicting consumer satisfaction. Theoretical and managerial implications for pharmaceutical marketers are discussed. 相似文献
24.
Vedhara K Nott KH Richards SM Bradbeer C Davidson EA Ong EL Snow MH 《AIDS patient care》1995,9(6):276-280
Despite uncertainty over their reliability, CD4+ cell counts are used extensively in both clinical and research settings to document progression in HIV infection. We examined, therefore, whether the performance of a simple statistical test would facilitate greater accuracy in the use of this marker. CD4+ cell count data were collected from a cohort of deceased (N = 60) and living HIV-positive gay men (N = 100). Pearson's product moment correlation coefficients were calculated for each individual in order to examine the association between CD4+ counts and time since diagnosis. Correlations of 0.7 or greater were obtained in approximately 50 percent of cases in each cohort. For these individuals, CD4+ cell counts were deemed to be a reliable indicator of rate of progression. The results suggest that the proposed technique ensures greater precision in the use of CD4+ cell counts and that the technique cna be used in individuals with either complete (deceased patients) or partial (living patients) CD4+ data. 相似文献
25.
54 sporadic colorectal cancers were analyzed for aberrations in the K-ras oncogene. DNA was extracted from frozen tissues obtained from surgical resection and analyzed for mutations in codons 12, 13 and 61 of the K-ras oncogene using single strand conformation polymorphism analysis (SSCP) and direct sequencing. Point mutations in the K-ras oncogene were found in 26/54 (48%) cases, all of which resulted in amino acid substitutions. No other types of mutations (e.g. insertions or deletions) were found. 4 of the mutations were at codon 12, 22 in codon 13 and only 1 was a codon 61 mutant. G-->A transitions were found to be predominant. A remarkable finding was the high preponderance of (13)Gly-(13)Ser mutations (54%). No correlation was observed between K-ras mutations and tumor location, Dukes' stage, differentiation levels, age or sex of the patient. 相似文献
26.
G Tr?en W Eskild S H Fromm L M De Luca D E Ong S A Wardlaw S Reppe R Blomhoff 《The Journal of nutrition》1999,129(9):1621-1627
The suggested function of cellular retinol-binding protein type I [CRBP(I)] is to carry retinol to esterifying or oxidizing enzymes. The retinyl esters are used in storage or transport, whereas oxidized forms such as all-trans or 9-cis retinoic acid are metabolites used in the mechanism of action of vitamin A. Thus, high expression of human CRBP(I) [hCRBP(I)] in transgenic mice might be expected to increase the production of retinoic acid in tissues, thereby inducing a phenotype resembling vitamin A toxicity. Alternatively, a vitamin A-deficient phenotype could also be envisioned as a result of an increased accumulation of vitamin A in storage cells induced by a high hCRBP(I) level. Signs of vitamin A toxicity or deficiency were therefore examined in tissues from transgenic mice with ectopic expression of hCRBP(I). Testis and intestine, the tissues with the highest expression of the transgene, showed normal gross morphology. Similarly, no abnormalities were observed in other tissues known to be sensitive to vitamin A status such as cornea and retina, and the epithelia in the cervix, trachea and skin. Furthermore, hematologic variables known to be influenced by vitamin A status such as the hemoglobin concentration, hematocrits and the number of red blood cells were within normal ranges in the transgenic mice. In conclusion, these transgenic mice have normal function of vitamin A despite high expression of hCRBP(I) in several tissues. 相似文献
27.
T. S. Ong 《Documenta ophthalmologica. Advances in ophthalmology》1982,52(2):355-361
This Capsular Lens (ONG, type IV, to be called O.C.L.) has been developed for routinely performed extracapsular cataract extraction with lens implantation. The fundamental surgical procedure was based on continuing experience with the bimanual aspiration-irrigation technique and system developed by the author in 1971. The biomechanical properties of the asymmetric partly flexible, haptic loops are designed to give tensionfree fixation in two capsular pockets. The plano-anterior position of the lens ensures well-defined irido-lenticular clearance and proper alignment of the convex side with the posterior capsule. Consequently no iridectomy or iridotomy is needed for proper aqueous flow. 相似文献
28.
Most children with benign childhood epilepsy with centrotemporal spikes have few seizures, and some have only one. We describe two children with interictal and ictal findings consistent with this epileptic syndrome but with severe intractable seizures and cognitive decline that resulted in consideration for epilepsy surgery. Spontaneous remission occured in one child; the other is still young. Despite the high seizure burden and cognitive decline, surgical consideration should be withheld, as these seizures are likely to remit. 相似文献
29.
Rosai-Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy, is a rare but distinct clinicopathologic entity characterised histologically by a benign s histiocytic proliferation. Isolated involvement of extranodal sites without concomitant nodal disease is rare. We describe the pathological features of 2 cases of Rosai-Dorfman disease that were clinically confined to the skin. In both male adult Chinese patients, proliferation of histiocytes was accompanied by S-100 protein expression demonstrated immunohistochemically within the histiocytes. The pathology of Rosai-Dorfman disease and its microscopic differential diagnoses are discussed. 相似文献
30.
We report an unusual case of focal nodular hyperplasia (FNH) occurring in a 19-month-old female without a typical central fibrous scar. Ultrasound demonstrated a solid, hypoechoic, highly vascular mass situated in the left lobe of the liver. Computed tomography showed a solid mass with no evidence of a central fibrous scar. A hepatic angiogram demonstrated enlarged right and left hepatic arteries supplying the vascular tumour, with early venous drainage into the inferior vena cava; a feature which has not been previously described. Surgical resection was carried out and a solid, nodular tumour measuring 9 x 4 x 4 cm was removed. The diagnosis of FNH was made histologically. The characteristic imaging findings of FNH will be discussed and a review of the literature of FNH in children will be presented. 相似文献